/**
 * spi机制是来自dubbo的spi
 * http://blog.csdn.net/jdluojing/article/details/44947221
 * http://my.oschina.net/candiesyangyang/blog/202320
 * http://blog.csdn.net/quhongwei_zhanqiu/article/details/41577483  #动态编译
 **/